Folding structure

ABSTRACT

The invention relates to a folding structure provided with a lock structure for the folding leg stud, which is capable of releasing the respective locked state by pressing the lock lever being in almost the same standby position even when the leg stud is deployed or folded. In this folding structure, even when the lock device as described above is used, the leg stud is allowed for compact storage without taking much space and thus a highly reliable folding structure can be provided.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application is a continuation of U.S. patent applicationSer. No. 10/373,407, filed Feb. 24, 2003, which claims priority ofJapanese Patent Application Nos. 2002-059595, filed Mar. 5, 2002,2002-121238, filed Apr. 23, 2002 and 2002-200673, filed Jul. 9, 2002,which are incorporated herein by reference in their entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a folding structure having a lockdevice for locking a leg stud foldably mounted on a basal plate such asa top board or a seat board in a deployed position and a folded positionrespectively.

2. Description of the Related Art

In the related art, as a folding structure such as a desk in which afoldable leg stud is locked, a lock device disclosed in JapaneseExamined Utility Model Publication No. 61-32507 is known. In thisstructure, since the leg stud is locked when it is in the deployed statebut not in the folded state, there arise problems such that it mayunexpectedly move in the deploying direction when the folded leg stud islifted up for transportation.

Therefore, it is desired that the leg stud be locked not only in thedeployed state, but also in the folded state.

Since the locking positions of the leg stud between the deployed stateand the folded state are away from each other by the extentcorresponding to the rotational angle of the leg stud, a lockingstructure including separate locking members is conceivable. However,there is a drawback that the structure is increased in size and incomplexity.

Therefore, deployment of a lock device in which locking and unlockingoperations of the leg stud can be performed by means of an identicallock lever both in the deployed position and a the folded positionanalogously has been expected.

On the other hand, in the folding structure provided with this type oflock device, since the leg stud is folded over the lock device, theheight in the folded state increases correspondingly.

Therefore, there are recognized problems in that an extra space forstorage is required and in that they take up much space when it isstacked one on another.

SUMMARY OF THE INVENTION

With such problems in view, it is a first subject of the invention toprovide a reliable locking structure of the folding leg stud in whichthe respective locked states may be released by pressing a lock lever inthe standby position toward the basal board both for deploying andfolding the leg stud.

It is a second subject of the invention to provide a locking structureof the folding leg stud provided with a stopper on a supporting bracketfor rotatably attaching the leg stud for limiting the deployed positionand the folded position of the leg stud so that the overall structure issimplified and thus the costs are saved.

With the drawbacks described above in view, it is a third subject of theinvention mainly to provide a novel folding structure in which the legstud can be folded without taking much space even with the lock deviceas described above.

It is a fourth subject of the invention to provide a reliable foldingstructure that allows for compact storage.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded perspective view of a lock device in accordancewith a first embodiment of the invention in the mounted state;

FIG. 2 is a perspective view showing a table in accordance with thefirst embodiment;

FIG. 3 is a perspective view of the lock device showing a state in whichthe leg stud is in the folded position;

FIG. 4 is a side view of the same;

FIG. 5 is a perspective view of the lock device showing a state in whichthe leg stud is in the deployed position;

FIG. 6 is a side view of the same;

FIG. 7A is a partial side view of the lock device showing a state inwhich the leg stud is in the deployed position;

FIG. 7B is a partial side view of the lock device showing a state inwhich the leg stud is in the folded position;

FIG. 8 is an exploded perspective view showing the mounted state of thelock device for a table in accordance with a second embodiment;

FIG. 9 is a side view of the lock device in a state in which the legstud is in the folded position;

FIG. 10 is a perspective view of a table in accordance with a thirdembodiment of the invention;

FIG. 11 is a front view of the leg stud in a folded position;

FIG. 12 is a perspective view of a table in accordance with the fourthembodiment;

FIG. 13 is a front view of the same;

FIG. 14 is an exploded perspective view of a principal portion of thethird embodiment;

FIG. 15 is a perspective view of the principal portion in a state inwhich the leg stud is in the deployed position;

FIG. 16 is a perspective view of the principal portion in a state inwhich the leg stud is in the folded position;

FIG. 17 is a side view of the principal portion in a state in which theleg stud is in the deployed position;

FIG. 18 is a side view of the principal portion in a state in which theleg stud is on route between the folded position and the deployedposition;

FIG. 19 is a side view of the principal portion in a state in which theleg stud is in the folded position;

FIG. 20A is a partial side view showing the locking state of the lockdevice in a state in which the leg stud is in the deployed position;

FIG. 20B is a partial side view showing the locking state of the lockdevice in a state in which the leg stud is in the folded position;

FIG. 21 is a partial perspective view showing a leg stud in accordancewith another embodiment;

FIG. 22 is a perspective view of the lock device showing a state inwhich the leg stud is in the deployed position in accordance with afifth embodiment;

FIG. 23 is a perspective view of the lock device showing a state inwhich the leg stud is in the folding position in accordance with a fifthembodiment; and

FIG. 24 is a side view of the lock device showing a state in which theleg stud is in the deployed position in accordance with a fifthembodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings, an embodiment in which a foldingstructure is applied to a table will be described.

A table T1 in the first embodiment shown in FIG. 2 comprises a top boardA, a pair of leg studs 5 mounted on the top board A so as to berotatable between the deployed position and the folded position, and alock device 1 for locking the leg stud 5 in the deployed position and inthe folded position.

In the figure, the reference sign C designates a proximal cap of the legstud, D designates a height adjustment screw of the leg stud, Edesignates a caster, F designates a side end cap of the leg stud, and Gdesignates a horizontal adjustment screw.

The leg stud 5 in the figure comprises a supporting leg portion 5 a anda leg base portion 5 b extending in the fore-and-aft direction at thelower end thereof.

The leg stud 5 is rotatably attached to the supporting bracket 2 fixedon the backside of the top board A with a first pin P1 via a cam bracket3 of the lock device 1 provided at the upper end of the supporting legportion 5 a so as to be rotatable between the deployed position and thefolded position.

The lock device 1 comprises, as shown in FIG. 1 through FIG. 6, thesupporting bracket 2 including a lock lever 4 rotatably attached theretowith a second pin P2 and the cam bracket 3 to be rotatably attached tothe supporting bracket 2 with the first pin P1 in combination.

In other words, the supporting bracket 2 comprises a basal plate portion20 integrally therewith, and is secured integrally on the backside ofthe top board A with a tap screw 12.

The supporting bracket 2 includes a side plate 2 a, whereof the end onthe leg stud side forms a deployment stopper 21 defining a prescribedangle (angle of deployment of the leg stud; 90 degrees in the exampleshown in the figure) with respect to the top board A.

Therefore, the angle of deployment of the leg stud 5 may be determinedto a desired angle by adjusting the angle of that end, that is, thedeployment stopper 21, with respect to the top board A.

The lower edge of the side plate 2a of the supporting bracket 2 isprovided with a recess serving as a lock pin stopper 22, which will bedescribed later, and a fold stopper 23 formed at the lowest edge thereoffor supporting the leg stud 5 (the supporting leg portion 5 a in thisembodiment) in a folded position.

The lock lever 4 is rotatably attached to the side plate 2 a of thesupporting bracket 2 with the second pin P2 in the position away fromthe position in which the first pin P1 is passed through, so that it iscapable of tilting.

A coil spring 8 is routed between the lock lever 4 and the supportingbracket 2 via the hooks 9 fixedly provided thereon respectively forurging the lock lever 4 in the locking direction (the direction in whicha lock pin 7 moves toward the top board A).

The lock lever 4 has a pair of left and right side plates 4 a eachformed with a hole for passing the second pin P2 at the midway thereof,and is provided with the lock pin 7 that serves as a locking portionfixedly at the front end, and a lever handle 41 that serves as anoperating strip molded at the rear end integrally therewith with a bentportion interposed therebetween.

The lever handle 41 may be covered with resin or rubber to improve atactile impression.

The cam bracket 3 fixed on the leg stud 5 has a channel shape in crosssection, and the left and right side plates 3 a thereof serve as lockingcam strips 30. The bottom of the channel extends outward to form a foldreceiving surface 36 for receiving the fold stopper 23, which will bedescribed late, when it is brought into contact therewith.

The locking cam strip 30 comprises a deployment lock receiving portion32 and a fold lock receiving portion 35, and a trace cam 34 formedbetween the receiving portions 32, 35, so that the lock pin 7 of thelock lever 4 is always kept in contact therewith by the urging force.

The locking cam strip 30 is formed with the fold lock receiving portion35 in the position where the lock pin 7 engages so that the lever handle41 is disposed between the folded supporting leg portion 5 a and the topboard A in the standby position, that is, in almost parallel therewith,when the leg stud 5 is folded (See FIG. 3, FIG. 4).

In the case of the example shown in the figure, the locking cam strip 30is formed with a notch to form a passage section 33 on the proximal sidealong the supporting leg portion 5 a in such a manner that the lock pin7 is fitted into the space between the locking cam strip 30 and thesupporting leg portion 5 a when the leg stud 5 is folded, and is formedwith the fold lock receiving portion 35 recessed in the passage section33 in the position orthogonal thereto.

The fold lock receiving portion 35 is adapted to be in alignment withthe lock pin stopper 22 in a position in which the leg stud is folded asshown in FIG. 3 and FIG. 4.

The opened side of the passage section 33 continuing into the fold lockreceiving portion 35 projects as a lock claw portion 31 and constrainsthe lock pin 7 even when a force of the leg stud 5 in the deployingdirection is exerted thereon.

The locking cam strip 30 is formed with a deployment lock receivingportion 32 in the position away from the fold lock receiving portion 35to the extent corresponding to the angle between the deployed positionand the folded position of the leg stud 5 about a fulcrum to which theleg stud 5 is rotatably attached (P1).

When the leg stud 5 is deployed as shown in FIG. 5 and FIG. 6, the lockpin 7 engages the deployment lock receiving portion 32, and in thatposition, the lever handle 41 takes almost the same position as thestandby position that is taken when the leg stud 5 is folded.

In such arrangement, when the leg stud 5 is deployed, the supporting legportion 5 a is brought into contact with the deployment stopper 21 ofthe supporting bracket 2, which defines a locking surface R1, forpreventing further rotation as shown in FIG. 7A, and the lock pin 7 ofthe lock lever 4 engages the deployment lock receiving portion 32 thatforms a deployment locking point R2 for locking the leg stud 5 in thedeployed position.

At this moment, the lever handle 41 takes the standby position away fromthe backside of the top board A in substantially parallel therewith asshown in FIG. 5 and FIG. 6.

When the lever handle 41 is pressed toward the top board (the directiona in the figure) and the lock lever 4 is rotated about the second pinP2, the lock pin 7 comes out from the deployment lock receiving portion32 and thus is released therefrom. Then the leg stud 5 is rotated in thefolding direction (the direction b) about the first pin P1, and isdisplaced to the locking surface R5 on which the leg stud 5 is broughtinto contact with the fold stopper 23 (See FIG. 6, FIG. 7B).

In order to rotate the leg stud 5 in the folding direction, by movingthe hand away from the lever handle 41, the lock pin 7 is tilted againstthe trace cam 34 formed on the edge of the locking cam strip 30 by aurging force, and in the folding position shown in FIG. 4, it is movedfrom the passage section 33 over the deployment lock claw portion 31 andthen is automatically fitted into and engaged with the fold lockreceiving portion 35, and thus is constrained by the fold locking pointR3 and the bottom dead center of the lock lever R4, so that the reverserotation of the leg stud 5 in the deploying direction (the direction c)is constrained (See FIG. 7 b).

In this embodiment, the first pin P1 is set slightly below the secondpin P2, and the locking points R2, R3 between the lock pin 7 and therespective receiving portions 32, 35 are positioned lower (higher inFIG. 7) than a line segment between the P1 and P2 so as to constrain thereverse rotation of the leg stud 5.

As described above, the lever handle 41 is disposed between the leg stud5 and the top board A in almost parallel therewith when the leg stud 5is folded, and moves back to the position almost the same as the standbyposition which is taken when the leg stud 5 is deployed (See FIG. 3,FIG. 4).

In order to deploy the leg stud 5 again from the folded position, thelever handle 41 is pressed toward the top board A in the direction aanalogously, the leg stud 5 is tilted in the deploying direction aboutthe first pin P1 while tilting the lock lever 4 about the second pin P2,then the lock pin 7 is freed from the fold lock receiving portion 35 andis allowed to move over the lock claw portion 31 and get out from thepassage section 33.

Since the lock pin 7 gives a force to the leg stud 5 in the deployingdirection within the range of its rotational trajectory when the legstud 5 is kept in a stationary state, the leg stud 5 is urged in thedeploying direction and thus it can easily be deployed.

Subsequently, the leg stud 5 is gripped and rotated in the deployingdirection (direction c), and is displaced to the position where it comesinto contact with the deployment stopper 21 shown in FIG. 6.

In this case, the locking pin 7 that is not subjected to a pressingforce now is brought into contact with and moved along the trace cam 34of the locking cam strip 30 by a resilient force, and then isautomatically fitted into the deployment lock receiving portion 32 inthe position where the leg stud 5 is brought into contact with thedeployment stopper 21.

As described above, the standby position of the lever handle 41 at thismoment is almost the same position as the standby position that is takenwhen the leg stud 5 is folded.

In this embodiment, an angle formed by the deployment stopper 21 definedby the edge of the side plate 3a of the supporting bracket 3 and the topboard A is the angle at which the leg stud 5 is held. Therefore, theangle of the leg stud 5 when being deployed is not limited toperpendicular, but it may be set to a desired angle, such as taperedlegs that are broaden toward the floor.

Likewise, the angle formed between the leg stud 5 and the top board A inthe folded position is determined by the distance from the top board(height) of the fold stopper 23. Therefore, the leg stud 5 in the foldedstate is not necessarily in parallel with the top board A as the exampleshown in the figure, but the folded position may be set at any desiredangle by varying the height of the fold stopper 23.

Since this embodiment comprises the supporting bracket 2 having the locklever 4 rotatably attached thereon and the cam bracket 3 as describedabove, it may be mounted freely irrespective of the types or theconfigurations of the leg stud 5.

In other words, while the case where the leg stud 5 is T-shape in planview is shown in the embodiment, it may be any other configuration.

For example, as a table T2 in the second embodiment shown in FIG. 8 andFIG. 9, when the leg stud 5 is U-shape in plan view or inverted angularU and comprises a pair of supporting legs 5 a′ and an upper horizontalmember 5 c connecting the upper ends thereof, the supporting bracket 2of the lock device 1 and the cam bracket 3 are increased in width andset to have a height not more than the height of the upper horizontalmember 5 a.

The fold stopper 23 is disposed between the deployment stopper 21 andthe lock pin stopper 22, so as to be able to come into contact with thefold receiving surface 36 of the upper horizontal member 5 a in thefolded state.

The spring 8 is fitted on the second pin P2, and engaged with the locklever 4 at one end and with the bottom of the channel of the supportingbracket 2 at the other end, so as to urge the lock lever 4 in thelocking direction.

Since other constructions are the same as those of the lock device 1 ofthe table T1 described in the first embodiment, the identical parts aredesignated by the identical numerals and will not be described again.

A table T3 in the third embodiment shown in FIG. 10 and FIG. 11comprises the top board A, the leg stud 5 rotatably attached to the topboard A so as to be capable of being deployed and folded freely, and alock device 1 for locking the leg stud 5 in the deployed position and inthe folded position.

The leg stud 5 of this embodiment is substantially inverted U-shapecomprising a pair of supporting leg portions 51, and a horizontal member52 connecting the upper ends of the supporting leg portions 51.

The leg stud 5 is rotatably attached to the supporting bracket 2 fixedon the backside of the top board A with the first pin P1 via the cambracket 3 of the lock device 1 provided at the center of the horizontalmember 52 so as to be rotatably between the deployed position and thefolded position.

The horizontal member 52 has a center portion 52 a formed into thehorizontal surface, and both of the left and right ends 52 b inclinegradually inwardly or toward the inside of the leg studs in the deployedposition, that is, toward the top board A when the leg stud is folded.

In the example shown in the figure, as is clear from FIG. 14, thehorizontal member 52 is provided with a cylindrical portion 53integrally attached to the end thereof, a leg stud body 54 is fittedinto the cylindrical portion 53 from above in the figure, and aprotective cap 55 formed of synthetic resin or rubber is engaged fromthe lower side of the figure, so that both of them are secured to formthe supporting leg portion 51.

Though the protective cap 55 and the leg stud body 54 are fixed togetherwith a screw to form a single unit in the example shown in the figure,the way to fix them together as a single unit is not specificallylimited and the leg stud body 54 may be fixed directly to thecylindrical portion 53.

In such an arrangement, as shown in FIG. 11, the horizontal member 52 ofthe leg stud 5 is positioned away from the backside of the top board Adue to the existence of the lock device 1 when the leg stud 5 is folded.

On the other hand, since the supporting leg portion 51 is positionedclose to the top board A due to the inclination of the horizontal memberon both ends, it never project over the horizontal member 52.

FIG. 21 shows a supporting leg portion 51′ according to anotherembodiment.

In this case, a plate bracket 56 is integrally attached to the end ofthe horizontal member 52, and the bracket 56 is formed with a screwhole.

On the other hand, a leg stud body 54′ is formed of a wooden column, andformed with a recess 54 a′ on the upper inner side. The bottom wall ofthe recess 54 a′ is formed with a pair of upper and lower holes.

The bracket 56 is fitted into the recess 54 a′ and retained, and then areceiving portion 57 having cylindrical nuts integrally formed thereonis positioned from the outside, and each nut is fitted into the hole.

Then, a screw that is not shown in the figure is screwed through thescrew hole on the bracket 56 and the hole on the bottom wall that isaligned thereto into the nut of the receiving portion 57, so that thebracket 56 and the receiving portion 57 are secured.

Accordingly, the leg stud 5 having a supporting leg portion 51′ formedof pure wood can be used in the above described embodiment.

As a matter of course, the connecting structure between the supportingleg portion 51 and the horizontal member 52 is not limited to theembodiment described above.

When stacking the tables A in accordance with this embodiment, thethickness of the table A is not more than the thickness up to thehorizontal member 52, and thus it allows for a compact storage. In thisarrangement, it is possible to decrease the thickness of the table, butit is necessary to set the top board A to the length at least twice thelength of the leg stud 5.

Therefore, dephasing the left and right leg studs 5 in the lateraldirection so that they are positioned alternately is contemplated toreduce the length of top board A to some extent, but it also has alimit. In addition to it, it is required to increase the width of thetop board A.

Accordingly, a table T4 in accordance with the fourth embodiment shownin FIG. 12 and FIG. 13 has a construction in which the leg studs 5 arefolded one on another.

In this case, only the horizontal member 52 of one of the leg studs 5 isinclined so that the sides to which the supporting leg portions 51 areconnected come closer to the top board A when being folded. Therefore,the supporting leg portions 51 are disposed closer to the top board Awith respect to the center portion 52 a of the horizontal member 52 whenbeing folded.

Then, the supporting leg portions 51 of the opposite leg stud (5′ forthe convenience of explanation) are disposed so as to be overlaidthereon.

In this arrangement, the length of the top board A can be reduced asmuch as possible as shown in the figure, and the width can be determinedcorresponding to the width of the leg stud 5, thereby realizing furthersize reduction.

In this embodiment, the supporting leg portions 51 are formed in plateshape but not in column shape, and the dimensions thereof are determinedso that the height of the overlapped supporting leg portions 51 of theopposed separate leg studs 5 does not exceed the height of the centerportion 52 a of the horizontal member 52.

Here, in the tables T3, T4 according to the third and fourth embodiment,the same lock device 1 that is shown in FIG. 17 through FIG. 20 is used.

The lock device 1 of FIG. 17 through FIG. 19 is the same as the lockdevice 1 of the tables T2 in the second embodiment, and the lock device1 of FIG. 20 is different from the lock device 1 of the tables T1 and T2in the first and the second embodiment in that the fold stopper 23 isnot provided, and other constructions are the same.

In other words, the lock device 1 comprises a supporting bracket 2including the lock lever 4 rotatably attached thereto with the secondpin P2, and the cam bracket 3 to be rotatably attached to the supportingbracket 2 with the first pin P1 in combination.

The side plate 2 a of the supporting bracket 2 is formed with a recessat the lower edge thereof, which serves as the lock pin stopper 22, andthe fold stopper 23 is not formed as described above. Since otherconstructions are the same as the lock device of the precedingembodiments, the same parts are designated by the same referencenumerals and are not described again.

FIG. 17 shows a state in which the leg stud is deployed, whichcorresponds to FIG. 6 illustrating the first embodiment.

FIG. 19 shows a state in which the leg stud is folded, which correspondsto FIG. 4 illustrating the first embodiment.

FIG. 18 shows a state in which the leg stud is in the course of movingfrom the folded position to the deployed position.

FIG. 20A shows a locked state when the leg stud is deployed, FIG. 20B isan explanatory drawing showing a locked state with the leg stud folded,which correspond to FIGS. 7A and 7B illustrating the first embodimentrespectively.

Since the fold stopper 23 is not provided on the supporting bracket 2,the leg stud 5 does not come into contact with the supporting bracket 2when being folded.

Other constructions are the same.

In this embodiment, since the lock device 1 comprises the supportingbracket 2 including the lock lever 4 rotatably attached thereto and thecam bracket 3, it can be mounted freely irrespective of the types orconfigurations of the leg stud 5.

In other words, while the horizontal member 52 of the leg stud 5 wasinclined at both ends in the preceding embodiment, it may be anyarbitrary configurations such as a construction in which the horizontalmember 52 is bent at a right angle or a construction in which thehorizontal member 52 is bent with a shoulder.

The spring 8 may be fitted on the second pin P2, and engaged with thelock lever 4 at one end and with the bottom of the channel of thesupporting bracket 2 at the other end, so as to urge the lock lever 4 inthe locking direction.

The supporting bracket 2 may be formed with a side as a fold stopperthat comes into contact with the center portion 52 a of the horizontalmember 52 when being folded.

Material of the top board A or of the leg stud 5 may be metal, wood, andresin. What is essential is that the supporting bracket 2 or the cambracket 3 can be secured. The configuration is not limited to pipe, andmay be pure material, round material, or square material.

The target object to which the lock device 1 is attached is not limitedto the table, but may be a desk, a chair, or other furniture orstructures as far as the leg stud can be folded and deployed.

The dimensions of the supporting bracket or the cam bracket arearbitrary, and especially the length along the axis of rotation may bevery long. Though a single lock device is provided for each leg stud, itis also possible to provide a plurality of lock devices in the centerportion of a single horizontal member.

The deployment lock receiving portion 32, the fold lock receivingportion 35 and the intermediate cam surface on the cam bracket 3 are notlimited to the examples shown in the figures, but the cam surface may beprovided in a plurality of positions separately.

Though the example in which the cam bracket 3 includes a pair of lockingcam strips 30 is shown, it is also possible to provide in a singleposition.

FIG. 22 to FIG. 24 show a fifth embodiment of this invention.

In this embodiment, a horizontal member 52 provided of a stand stopper80 which projects toward a top board.

The stand stopper 80 is box-shape or block-shape, and integrallyattached to the center portion 52 a of the horizontal member 52.

In this case, the stand stopper 80 comprises a rear plate portion 81, atop plate portion 82, and the left and right side plate portions 83.

The end of the rear plate portion 81 is welded to the horizontal member52, and the end of the left and right side plate portions 83 are weldedto the projected portion 36′, which is prolonged from the fold receivingsurface 36 of the cam bracket 3 and projected from the horizontal member52.

The basal plate portion 20 of the supporting bracket 2 is set up widely,so as to be able to come into contact with the top of the plate portion82 of the stand stopper 80 when the leg stud 5 is deployed.

The stand stopper 80 is not limited to the configuration shown in thefigures, and may be any arbitrary configurations to have enough intency.

When the leg stud 5 is deployed, the deployment stopper 21 contacts withthe projected portion 36′ and constrains the fold receiving surface 36.

Furthermore, the stand stopper 80 contacts with the basal plate portion20 and constrains the supporting bracket 2.

And the space between the horizontal member 52 and the supportingbracket 2 is filled up with the stand stopper 80.

Accordingly, the leg stud 5, it is deployed and stood up, can be keptstrong and stable in the above described embodiment.

In addition, when the leg stud 5 developed or is folded up, the tip ofthe cylindrical portion 53 is formed hemispherical, and which isprojected to the top board A side (below in FIG. 22) rather than thehorizontal member 52.

Therefore the position of the cylindrical portion 53 (the projectedposition from the horizontal member 52) is defined by the rotation locusat the tip of the cylindrical portion 53 as a relative relation with theposition of the 1st pin P1 so that there may always be untouched the topboard A when the leg stud 5 is moving during developed to be folded up.

In this embodiment, the stand stopper 80 showed the case where it formedapart from the horizontal member 52, however the stand stopper 80 may beformed in the horizontal member 52 as a part of it.

In short, it is possible to vary in design without modifying the scopeof the invention as a matter of course.

As is described thus far, in the folding structure in accordance withthe present invention, the supporting bracket including a lock leverthereon is secured on the basal plate, a cam bracket is fixed on the legstud, and both of them are rotatably mounted, so that the leg stud canbe rotatably mounted to the basal plate.

The present invention provides a reliable lock structure of the foldingleg stud in which locking state may be released by pressing the locklever in the standby position toward the basal plate, even when the legstud is deployed, or folded.

In addition, the overall structure is simplified and thus the costs maybe reduced by providing a stopper that constrains the deployed positionand the folded position of the leg stud on the supporting bracket towhich the leg stud is rotatably mounted.

Further, in the folding structure in this invention, by inclining bothend of the horizontal member of the leg stud toward the basal plate, thesupporting leg portions at both ends of the horizontal member can bedisposed in contact with the top board while the horizontal member ofthe leg stud is positioned away therefrom when being folded via a lockdevice.

Consequently, the size of the basal plate of the folding structure suchas the top board is not constrained significantly by the leg stud, andthus the basal plate can be downsized. When stacking them one onanother, since it can be reduced in thickness as much as possible, it issuperior in space saving.

1. A folding structure comprising: a supporting bracket fixed on thebasal plate such as a top board or a seat board, and provided with a legstud rotatably mounted at one end thereon; a lock lever rotatablysupported at the other end of the supporting bracket, provided with alocking portion formed of a lock pin at one end and an operating stripat the other end, and urged in the locking direction; and a locking camstrip fixed to the leg stud so that the locking portion is always incontact therewith; the locking cam strip further comprising: a fold lockreceiving portion formed in the position where the locking portionengages in a standby position in which the operating strip is disposedbetween the folded leg stud and the basal plate when the leg stud isfolded, and a deployment lock receiving portion provided in the positionaway from the fold lock receiving portion by the angle corresponding tothe angle between the deployed position and the folded position of theleg stud about a fulcrum at which the leg stud is rotatably attached,and formed in the position where the locking portion engages when theleg stud is deployed with the operating strip taking almost the sameposition as the standby position which is taken when the leg stud isbeing folded; wherein the respective locking state is released bypressing the lock lever in the standby position toward the basal platewhen the leg stud is in the deployed position and in the foldedposition.
 2. A folding structure as set forth in claim 1, wherein thelocking cam strip is formed on a side plate of the cam bracket securedto the leg stud, and wherein the cam strip comprises a passage sectionto which the locking portion comes into the space between the lockingcam strip and the leg stud when folding the leg stud, and a fold lockreceiving portion recessed in the passage section for engaging thelocking portion.
 3. A folding structure as set forth in claim 1, whereinthe supporting bracket is formed at the end thereof with a recessedlocking portion stopper that comes in alignment with the fold lockreceiving portion displaced when the leg stud is folded for rotatablysupporting the locking portion.
 4. A folding structure as set forth inclaim 1, wherein the supporting bracket is formed with a deploymentstopper at one end thereof for determining the deployed position of theleg stud by being brought into contact with the leg stud when the legstud is deployed.
 5. A folding structure as set forth in claim 1,wherein the supporting bracket is formed with a fold stopper at thelowest edge thereof for determining the folded position of the leg studby being brought into contact with the leg stud when the leg stud isfolded.
 6. A folding structure as set forth in claim 1, wherein the pairof leg studs provided on both end portions of the folding structurecomprises a pair of supporting leg portions and a horizontal member forconnecting the supporting leg portions, and wherein each horizontalmember is formed in such a manner that the sides to which the supportingportions are connected move closer to the basal plate when the leg studis folded, so that the supporting leg portions are disposed in thepositions closer to the basal plate with respect to the horizontalmember when the let stud is folded.
 7. A folding structure as set forthin claim 1, wherein the pair of leg studs provided in the both endportions of the folding structure each comprises a pair of supportingleg portions and the horizontal member for connecting the supporting legportions, and are adapted to be folded in such a manner that thesupporting leg portions of the opposed leg studs are placed one onanother, and wherein only one of the horizontal members is formed insuch a manner that the sides to which the supporting leg portions areconnected move closer to the basal plate when the leg stud is folded sothat the supporting leg portions are disposed closer to the basal platewith respect to the horizontal member when the leg stud is folded, andwherein the supporting leg portions on the side of the other horizontalmember are disposed so as to be superimposed on the supporting legportions on one side.
 8. A folding structure as set forth in claim 6,wherein the horizontal member is obliquely inclined at both ends thereofand the supporting leg portions are secured at the ends thereof.
 9. Afolding structure as set forth in claim 1, wherein the pair of leg studsprovided on both end portions of the folding structure comprises a pairof supporting leg portions and a horizontal member for connecting thesupporting leg portions, and wherein the horizontal member is formedwith a stand stopper which is brought into contact with a basal plateportion of the supporting bracket fixed on the basal plate when the letstud is deployed.